The invention relates to a television camera equipped with a color-separating prism assembly disposed behind the objective. The assembly comprises a plurality of surfaces which adjoin dichroic layers of mutually different colors. In the camera, the separated light beams which emerge from the prism assembly, are transmitted to camera tubes. In the prism assembly, passing in the direction of the light which enters the prism assembly, there are provided, twice in succession, a plane air-glass transition and a dichroic layer. Each layer encloses an angle with the air-glass transition and adjoins a plane glass surface. At least one air-glass transition and the associated dichroic layer enclose an angle smaller than 30.degree. with a plane which is normal to the nonreflected optical axis.
Such a television camera is known from U.S. Pat. No. 3,202,039 (Netherlands Patent Specification No. 113,911). The known television camera has the advantage that the glass-length of the prism assembly to be traversed by the light can be comparatively small. The prism assembly thus obtained can be comparatively compact because the totally reflecting air-glass transitions are plane. As a result of this, one zone of such an air-glass transition may serve both as an entrance surface for the light in the relevant prism section and as a totally reflecting surface for the light which is reflected by the dichroic layer associated with the air-glass transition. Since at least one air-glass transition and the associated dichroic layer enclose an angle smaller than 30.degree. with a surface which is normal to the nonreflected optical axis, annoying polarization effects in the traversing light or color variations across the lens pupil and/or the image field are avoided.
In the known television camera the axes of the three camera tubes are arranged in different directions relative to each other. An arrangement of camera tubes in which the tube axes extend in different directions has the drawback that external magnetic fields, for example the earth's magnetic field, have a different influence on the electron beam in each tube. When the position of the television camera is changed this may give rise to registration errors. A further drawback is that with the known set-up of the prism assembly and camera tubes a compact design is not easy to realize.